These numbers reflect the dimensions of a "national pressure cooker," to use APA's term, and it's causing untold damage to physical and emotional well-being and relationships. "Given the potential health complications related to these behaviors, it is fair to say that stress is a major health problem in America," APA's report concludes.

Several factors contribute to the daily pressure felt by millions of Americans, ranging from finances and unemployment to traffic, crime and pollution. The intensity of this toxic mixture varies from market to market across the country, as does the level of stress.

Nowhere is the situation worse than in Detroit, which ranks as the most stressful metropolitan area in America, according to a new Bizjournals study.

Detroit is saddled with the highest unemployment rate, 7.2 percent, in any of the nation's 50 largest markets. It also has the group's worst murder rate. And it's among the 10 places with the most robberies, the slowest rates of income growth, the most heart attacks and the fewest sunny days.

Mix all of these factors together, and Detroit is cursed with America's ultimate recipe for stress.

Right behind Detroit on the stress index is another Great Lakes metro with its share of economic woes, Cleveland. It's burdened with the group's worst robbery rate, second-worst frequency of heart attacks and strokes, and fourth-worst unemployment rate. Others in 10 most stressful places America's 10 most stressful markets include St. Louis, Los Angeles, Memphis, Philadelphia and Atlanta.

Bizjournals created a 10-part formula to rank the stress levels in 50 leading metros, using data collected by several government agencies and private firms.

Virginia Beach and other less-stressful places

The outlook is much sunnier in Virginia Beach-Norfolk, Va., which ranks as America's least stressful metropolitan area.

Virginia Beach's slogan is "Live the Life," emphasizing its reputation as a relaxing destination for seashore vacations. It ranks among the nation's five best markets for healthy air, freedom from crime, stable employment and strong income growth.

Salt Lake City is the runner-up in the low-stress derby. It enjoys America's smallest unemployment rate, 2.6 percent, as well as light traffic, healthy citizens and low crime rates.

Other less stressful metros included Phoenix, Austin, Denver, San Diego, and Jacksonville, Fla.

Bizjournals cast a broad statistical net to identify the metros that subject their residents to unusually high or low amounts of stress. The following are the 10 indicators included in the study, along with a brief summary of the best and worst markets. For each category, Bizjournals also listed the top and bottom three metros in each category.

Unhealthy air: Six places, including Virginia Beach-Norfolk, don't experience any days of heavy pollution in a typical year, according to Environmental Protection Agency records. Riverside-San Bernardino, Calif., with 28.2 unhealthy days per year, is the worst.

Sunshine: Las Vegas and Phoenix soak up 85 percent of possible sunshine per year, leading the study group. Pittsburgh ranks as the gloomiest market at 45 percent. All figures come from the National Climatic Data Center and Weatherbase.

Robberies: San Jose has the lowest rate, 111.9 robberies per 100,000 residents, based on central-city records compiled in 2006 by the Federal Bureau of Investigation. Cleveland occupies last place with 947.1 robberies per 100,000.

Murders: The level of danger is lowest in Austin, with 2.8 murders per 100,000. The worst central-city ratio belongs to Detroit, 47.3 murders per 100,000 residents as of 2006.

Unemployment rate: Salt Lake City is the positive extreme, with a jobless rate of only 2.6 percent. Detroit takes another hit, as the latest figures from the U.S. Bureau of Labor Statistics show that 7.2 percent of its workers are unemployed.

Income growth: New Orleans is this category's surprise winner, increasing its per capita income by 45.8 percent between 2000 and 2006, based on U.S. Bureau of Economic Analysis data. Hurricanes Katrina and Rita drove thousands of poverty-stricken residents out of town in 2005, artificially inflating the market's income level. At the bottom is San Jose, with a virtually stagnant growth rate of 0.3 percent over six years.

Long-distance commuters: Traffic is exceptionally light in Buffalo, where only 6.5 percent of commuters hit the road for 45 minutes or more. New York City, at 31.0 percent, qualifies as the most congested market. (Figures for this and the next two categories come from the U.S. Census Bureau's 2006 American Community Survey.)

Families below the poverty level: The Washington market is the most affluent in the group, with just 4.7 percent of its residents living in poverty. Memphis has the worst poverty problem, 13.9 percent.

High mortgage payments: Few residents of Buffalo are bothered by enormous housing costs. Only 1.5 percent write checks for $3,000 or more per month. One-third of San Jose's residents (33.9 percent) spend at least that much, the nation's steepest ratio.

Deaths from circulatory-system diseases: Austin has the lowest number of deaths caused by heart failure, hypertension and stroke, a rate of 145.7 per 100,000 residents. The highest rate belongs to Pittsburgh, 441.4 deaths per 100,000. The Centers for Disease Control and Prevention collected these central-county statistics in 2004, the latest year for which figures are available.